Fog lights come on by themselves

[art5519]

This is totally bizarre, but putting it here in case anyone seen/heard anything like this. Basically woke up this morning and my 200 LC (09) fog lights are on. The car is locked and security light is flashing as expected. Unlocked the car, all the light switches are off. Started the car, turned lights on and off - the fog lights stay on, even though light switch for fog lights is off. BTW, there is a day lights that come on when I start the engine, the fog lights are different, not to be confused.

So, played around with turning the car on/off. Few times the fog lights went off, but then came back on within few seconds. Took the car to the dealer - about 30 minutes drive. Of course by the time I got there - the fog lights are off and work as expected.

Dealer did diagnostics and found no issues, told me they opened a case with Toyota and should hear back in couple of days on Monday.

We had pretty heavy rain all night long (car is parked outside). Suspecting this has to do with some electronics and possibly high humidity as a factor here, but lights turning on by themselves on a parked and locked car???

 

[Willy beamin]

Christine

 

[studawg]

First thing i would do is disconnect both battery terminals for about ten minutes, then reconnect.

 

[Desert Nomad]

It must be a relay or some wiring creating a short circuit, i had it happen at a car wash when the guy decided to wash the engine bay and set off all my aux lights.

I'd check which relays and fuses are related to the fogs check and make sure they're dry, check condition of wiring from the fog light housing untill engine bay.

 

[art5519]

Just to add the latest, after the dealer contacted Toyota they advised to check the sun roof drain tubes. Sure enough both tubes were clogged. From what it was explained to me by the dealer, when the tubes get clogged up - water starts to sip over them. The tubes go inside those bars that hold the windshield (forgive the terminology here). Apparently there are some electric switches that are on the way. As water starts dripping over the switches - you get the idea.

Basically, the dealer cleaned up the tubes, cleaned up the electric connectors (connector on one side even had corrosion), it's been a week now and everything seems to be working fine so far.

As a side note, I've had few weird intermittent issues with electronic functionality / components and beginning to suspect that this leak is the culprit (although not totally confident yet).

Long story short, get your sun roof drain tubes cleaned. The dealer mentioned that the damage could have been worse if the leak resulted in a short circuit of some major electronic component.

 

[studawg]

I woke up to the exact same thing the other morning on my 08, after several days of hard rain. Just the fog lights were on. I came here, found this thread, and thankfully @art5519 had come back to post up the resolution.

I first checked the driver side floor board, and sure enough, it was wet. Then went up to the sunroof drains and found a really weird looking green, dead beetle that was lodged in the top of the drain tube, blocking 90% of the opening. I vacuumed that out, then tried to run some weedeater line through, but I got hung up about 3 feet in. I removed the lower door trim and kick panel to let it dry out, and started looking around for the fog light relay. I ended up finding a tiny little bit of water in one of the connections, so I took a hair dryer and just started blowing hot air in there. I did all this with the negative terminal disconnected. It didnt take long with the hair dryer, after several minutes with it, I hooked the battery back up and all is well. No more fog lights. Never had any other electrical issues. My LC is normally garaged but had left it out for a few days while reorganizing the garage. We had had several days of very heavy rains and really humid conditions. All sunroofs leak a little, thats what the drains are for, but evidently, they seem to clog in the LC more than other vehicles because this has been a common problem on 80s, 100s and 200s.

Im starting to think that some of the electrical issues Ive seen with other 200s after a windshield replacement, aren't due to the windshield leaking, they are just due to clogged sunroof drains.

 

[ckkone]

Im starting to think that some of the electrical issues Ive seen with other LCs after a windshield replacement, aren't due to the windshield leaking, they are just due to clogged sunroof drains.

A picture of the sunroof drains would be very helpful.

 

[studawg]

Thats a picture looking down from above into the front left corner of the sunroof opening, with the the black fairing pressed down. The drain is the little round hole. Theres one on the passenger side as well.

 

[ckkone]

Great, thanks. I'm going to check mine tonight.

 

[Rigger]

Nice detective work! I’ll check mine, too.

Add this to the list:

Radiator crack
Heater tees
Sunroof drains

 

[4gotalot]

What about a filter made of a block of air filter foam cut to fit in the corners of the moon roof.

Its on my list of preventive maintenance. Thank you all for the heads up.

 

[PDXLX]

I had the same problem in my 100. It ended up being water entering the cabin at the base of the windshield, pooling on the relays, and shorting out.

 

[studawg]

I had the same problem in my 100. It ended up being water entering the cabin at the base of the windshield, pooling on the relays, and shorting out.

Aftermarket windshield?

The 100 series had some really funky windshield molding with metric rivets that had to be replaced with the exact same parts when the windshield was replaced. I have just recently learned from a glass guy that the 200 series does not have the same design.

 

[PDXLX]

Aftermarket windshield?

The 100 series had some really funky windshield molding with metric rivets that had to be replaced with the exact same parts when the windshield was replaced. I have just recently learned from a glass guy that the 200 series does not have the same design.

That was exactly the problem. The PO had the windshield replaced and instead of using rivets they drilled tech screws.

 

[BVCOTaco]

So just found this thread after searching for the cause of the water issue I just had on my '13. I have had a couple 80s and a 100 series and made me think it was the sunroof drains.
I took my '13 through the car was this evening and I heard something like water running above my head in the drive seat. A few second later a lot of water some out through the dome light and sunglasses holder. So we grabbed napkins and tried to mop up the water while still in the car wash. Then I noticed that both A pillars were also wet. After the car was ended and we were trying to clean up the napkins and water every where I pulled out of the car was and noticed the check engine light was on. When I got home, I plugged in my scan gauge and it is not reading the code. So I decided maybe I would leave the windows open on the car and turn the heater up in the garage to dry out the water inside. So I pushed the start button without stepping on the break to get the windows to operate, well on the second push WITHOUT stepping on the break it started.

We are leaving on Sunday for a weeklong camping trip in Southern Utah and Northern AZ, not I am not sure what to do. The nearest dealer is 2 hours away. Do you think an auto parts store's scan tool would get me the code?

 

[Romerca]

Thank you @art5519 for this post and follow up. Had this exact same issue with this continued rain here in California.

 

[nzeighty]

Havnt been on mud for a while
Brought a 200 6 months ago
Went through a car wash last night didnt realise i left the sunroof open because blind was closed : (
Woke up this morning and just fog light were on.
Did a google search and it sent me here : )
Will clean the drain holes today
Anybody know how to get to the electrical connections so can clean them?

 

[beuffalo]

This thread was a lifesaver. Thanks Art! We got dumped on in the last 24 hours and had this same issue overnight, got up in the morning to the fog lights on with everything in the off position on the stalks. Sure enough driver side sunroof drain was plugged up, little bit of wetness on the corner of the headliner on that corner of the sunroof, and upon further investigation the fog light relay was soaked. Pulled it in the garage and pulled the fog light fuse as well as unhooked the battery. Will get it dried out and hopefully all is well.

 

[pselb]

Dealing with this issue. Can someone tell me where the fog light relay is located? I pulled the fuse, but also have the side marker lamps staying on all the time.

 

[TailGator]

My thanks to this incredible forum! The foglights on my 2008 mysteriously came on this week and drained the battery. I was bracing myself for a potentially long and expensive process of trial and error. But the info in this forum helped me get to the root cause right away. A clogged sunroof drain caused water to be diverted down the driver's side A pillar and caused corrosion in some of the electrical junction boxes. Note the blue goo in the pictures below. Everything is fixed now.

I hope these photos help somebody else down the line.